Speed-indicating instrument



W. VAN GUJLDER. SPEED lNDICATfNG HIS APPHCATION FIL TBUMENT.

BHJNEIT, IQIB.

PatentedSept.

UNITED STATES PATENT OFFICE.

WALTER. VAN GUILDER, OF CHICAGO, ILLINOIS, KSSIGNOR TO STEWART-WmSPEEDOMETER CORPORATION, OF CHICAGO, ILLINOIS, A OORZPURATION-OF VIE-GINIA.

SPE'EBiNDiCATING INSTRUMENT.

Specification of hitters Patent.

Patented Sept. 28, 1920.

Application filed June 1?, 1918. Serial No. 240,555;

To all whom it way concern.

Be it known that I, llhrxrnn VAN Gijmnnu, a citizen of the UnitedStates, residing at Chicago, in the county of Cook and the State ofIllinois, have invented certain new and useful Improvements in Speed-Irulieutlng Instruments, of which the following is a specification.reference being had to the no (rompanying drawings, forming a partthereof.

The purpose of this invention is to pro vide on improved construction ofspeed in (lit-rating levioe having the magnet fixeththat is,non-rotating, the rotating element being a multi-polnr armature whichmay be comparatively light thereby adapting the instrument forindicating the speed of shafts to be rotated by light power, and Whosespeed of rotation would be materially reduced by the resistance of nspeed indi" eating device hm lug heavy parts to be rotated. It consistsin the elements and 'l'en" tures of eonetrurtion shown and (leseril'sedindicated in the claims.

In the drawings:

Figure l is an axial section of an instrument embodying this invention.

Fig. is a front elevation of the some with the cover member removed.

Fig 3 is a section at the line. 3-3, on Fig. l. i

Fig. 4 is a section at the line. 4-4. on

Fig. l.

The inetrument shown in the drawings comprises a casing, l, in whichthere is supported rigidly n magnet mount, 2, which is made ofnon-magnetic metal in the general form of a cup having at the top edgeor front edge an outwardlyextending flange, a. by which the mount issupported on the casing. The magnet element comprises two semi-annularmagnets. 4-. 4, whirh are fitted within the cup-shaped mounzt, beinglodged upon the bottom or back diaphragm thereof and against thecircular wall, said magnets while culled semi-annular, eing in fact eachslightly less than a halt circle. so that when they are positioned arestated in the. cup, two equal inter-polar go is exist. said magnetsbeing placed with t eir poles of fpposite name respectively facing eachother at opposite sides of said gaps. Said mount is preferably a castingand formed with inwardly-extending radial projections 22%, from itsannular walLventermg the interpolar gaps between the two magnets asstated and thereby further securely position the magnets in the mount.For further securing the magnets in the mount there is 'the oppositeside of the magnets from the bottom web of said mounts.- For assemblingthe parts as described and engaging the annular retaining plate, 5, periberallv with theoup-shaped mount as described, the retaining plate hasany convenient number,as shown, two diametrically opposite each other.0fperipheral projections, 5, and the TnOUIlt has two wrrespondinglysituated notches, 2 2. extending in from its open edge a short distance,each connecting with a groove, 2, formed in the inner wall of thecup-ehapedmount; so that said retaining plate may be introduced intoposition by entering its said projections through suid notches to thebottom thereof, and then rotating the plate to engage the projectionswith said grooves, as seen in Fig. 2. On the back wall of the case. 1,there is mounted on inunruly-projecting bearing stud, 7, on which thereis journaled a gear, 8, which is conveniently retained on the stud by acap screw. 9. This gear carries a multi-polar nrnmture, 12. at thecenter of which it is secured to said gear for rotation thereby. Asshown. the armature has an even number of poles, equally spaced, so thatthe relation of the poles to the two diametrically-opposite inter-polargaps of the magnet are at all times identical; that is to say, the sumof the distances of the armature poles from 17 and 18, there areprovided suitable jeweled bearings, 17 and 18, for the op osite ends ofthe spindle, 16. For the sa e of complactness the dra element of thedrag disk is depressed at its central part so that it is secured to itsspindle between the planes of the opposite sides of the magnet element,that is to say, in the central space of the annular structure comprisingsaid two semiannular magnets. dial plate, 20, is mounted upon the magnetmount, having a central opening through which the spindle extends forcarrying in front of said dial plate an index pointer, 21, mounted onthe spindie back of the spindle bearing in the arm, 18. The front of thecase may be closed by a cover, 25, comprising a transparent crystal, 26,through which the reading of the instrument may be observed. Forrotating the rotatable armature there is jour naled in the case a shaft,28, havin at its inner end a gear, 27 meshing with t e gear, 8, theouter end of said shaft being ada ted for driving connection in a mannerw ich will be understood from the drawings without explanation.

For calibrating the instrument there is mounted in relation to each ofthe semiannular magnets a shunt terminal pole piece, 3( of soft ironwhich is conveniently formed angle shaped as seen at Fig. 2, having oneflange provided with a slot, 31, by which the pole piece is adjustablymounted upon the ring, 5, by means of a screw, 32. The range ofadjustment of the pole piece with respect to the magnet is such as topermit the flange, 33, of the shunt terminal, 30, to project more orless across the inter-polar gap of the magnet, and thereby be ada ted toconduct a larger or'lesser portion '0 the flux across the gap, fordiminishing the amount of flux which is diverted by the poles of therotating multiolar armature through the drag element, t ereby varyingthe drag eiiect. This, it will be seen, will enable the assembler of themachine to make such adjustment as may be necessary to cause a givcnspeed to produce a given indication upon the dial, notwithstandingvariution in the strength of the magnets, and variation in theresistance of the biasing spring. That is to say, it facilitates adaptution of the biasing spring to the strength of the magnets. bymodification of the proportion of the magnet-strength which becomeseffective for producing drag.

For the purpose of adopting the instrument to he automaticallycompensated tortempen ature changes and also to automatically compensatefor changes in the magnet strength the interpolar gaps between themagnets, which as stated are in the main occupied by thc substance ofthe mount, which has the projections, 2, for engaging said intcrpolargaps to position the magnets fixedly are partly opened by cutting awaythe material of the mount inangular form as seen at 2, and for each gapthere is provided an angular or V-shaped soft iron armature piece, 35,mounted upon one end of the iii-metallic spring carrying arm, 36, theother end of which is secured to the mount, so that said sojt ironarmature piece may protrude more or less deeply into the iuterpolar gapaccording to the curvature of the bimetallic arm which carries thearmature, which is effected by the change of temperature. The member ofthe iii-metallic arm having the higher cocflieient of expansion being onthe inner side, as the temperature rises the arm will be straightenedwith the effect of carrying the armature piece back out of the gap, andwhen the temperature falls it will be more curved, carrying saidarmature piece toward or into the gap; which it will be understood willhave the client of diverting a larger amount of the magnetic flux fromthe rotating armature as the temperature falls, and ermitting a largerportion of the flux to be iverted b the rotating armature so as to beout by t e drag element as the temperature rises; thus compensating forthe diminution 'of drag which results from the rising temperature andthe increase which results from the falling temperature.

The arms, 36, being as stated, s ring arms, are adapted to yieldinglyresist t 1e tendency of the V-shapedarmature, 35, to move toward themagnet poles under the attraction of the magnet; and upon any decreasein the magnets strength, the armature piece. 35, will be retracted bythe spring arm away from the magnet poles, thereby diminishing theproportion of the magnetic flux passing through said armature piece, 35,and correspondingly increasing the proportion of flux passing throughthe poles of the revolving armature, 12. Similarly, any increase in themagnets strength causing the armature piece, to approach the magnetpoles, diminishing the proportion of flux passing through the revolvingarmature. It will be understood that these changes of proportion of fluxpassing through the rcvolving arma ture, correspondingly affects thedrag on the drag element, 1!), increasing the drag relatively upondecrease of magnet strength, and decrealing it relatively upon increaseof magnet strcngth, thus automatically compensating for such changes inmagnet strength.

I have indicated that the devi e liS "'ii7t l has two interpolur gapsand a r tating armature ll l' 'i'idill with an even number of poles; butit Wiil be obvious that the result sought by this feature of The constrution requires only that the number of armature poles bc a multiple of henumhcr of magnet gaps, there being a plurality of said gaps. Thepreferred"number of gaps being two, there will be an even number ofarmature poles, as specifically shown and descri l'Jtt l.

I claim:-

I. In a magncticspccd indicating instrument in combination with anon-rotating magnet; the multi-polar armature device mounted forrotating its polespast the magnet poles; an electrically conductive dragdisk positioned and pivotally mounted for oscillation in a planeintermediate the magnet poles and the path of rotation of the armaturepoles, and means for biasing the disk in respect to the direction of itsoscillatory movement; the magnet element comprising a plurality of eiwilly-dimensioned magnets each having both its poles in the same planetransverse to the axis of rotation of the. armature device, and thepoles of each proximate respectively to the oppositely-named poles ofanother. for forming in a circle about said axis as many interpolar gapsbetween poles of opposite names of dit'lcrcnt magnets, as the entirenumber of magnets of the nu gnet device; the mount for the magnetconsisting of a uoirmagnetic substance encompassing and occupying theinter-polar gaps otsaid magnets, and a lateral annular retaining plateat one side of the magnets peripherally engaged with said mount.

2. In the structure defined in claim I. toregoii'ig, the mount having abayonet-lock slot and the plate having a peripheral projection adaptedto he entered through and engaged with said bayonet lock slot by angularmovement of the plate, for securing the magnet against disphu-cmci'it ofthe mount.

3. In a magnetic speed indicating instru ment comprising a fixed magnetelement having an interpolar gap,- a revolving interrupted armature. anda drag element intcrmediate the magnet and said armature; a temperaturecompensating device consisting of a soft iron armature piece and abi-metallic arm Which carries said armatur' piece on its movable endproximate to the interpolar gap of the magnet for moving it relativelyto said gap upon temperature changes deflecting said iii-metallic arm.

4. In a magnetic speed indicating instrunient comprising a fixed magnetelement having an interpolar gap, arevolving inter-- rupti-d armature,and a drag clement intermediate the magnet and said armature; acalibrating deviceconsisting of an adjustable pole piece or shuntterminal mounted adjacent to one pole of the magnet and adjustablerelatively thereto toward and from the other pole across the interpolargap.

5. In a magnetic speed indicating instrument such as defined in the lastclaim foregoing, the magnet element comprising a plurality of arcuateelements positioned in the same plane with substantially equalinterpolar gaps, one of the magnet poles at each gap being provided withthe adjustable pole terminal or shunt.

6. In a magnetic speed indicating element in combination with a magnetelement having an interpolar gap, a temperature compensating elementconsisting of a soft iron armature and a temperature-responsive carrierfor the same mounted at one point fixedly with respect to the magnet andcarrying the soft iron armature at a point on said carrier which movesresponsively to temperature change and at. a position for moving in onedirection toward both magnet pole. and in the opposite direction awayfrom both magnet poles.

T. In a construction such as set out in claim (3 foregoing. the armaturecarrier being a bi-metallic arm.

8. In a device such as defined in claim 6, the compensating armaturecarrier being a. bimetallic arm, mounted at one end fixedly with respectto the magnet and carrying the armature at the other end in the plant!of the magnet toward and from the interpolar gap.

9. In a magnetic speed indicating instru ment in combination with amagnet element, a drzu element and a flux deflecting armature tordeflecting the tlux through the drag element. amagnetstrength-change-compensating device comprising a soft ironarmature element positioned proximately to the magnet gap and a sprinsupport for the same mounted for yielting toward both poles in onemovement and reacting away from both poles in the opposite movement.

10. In a structure such as defined in claim 9 foregoing, the magnetbeing fixed and the flux-deflecting armature being multi-polar,positioned laterally with respect to the magnet and rotating, and thecompensating armature being carried by the spring support for movementradially toward and away from the interpolar gap of the magnet.

In testimony whereof, I have hereunto set my hand at hicago, Illinois,this 14th day of June, 1918.

- \VALTER VAN (iUILDER.

